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Upgrade guide

Migrate to v2 from v1

The transition from Powertools for Python v1 to v2 is as painless as possible, as we aimed for minimal breaking changes. Changes at a glance:

  • The API for event handler's Response has minor changes to support multi value headers and cookies.
  • The legacy SQS batch processor was removed.
Important

Powertools for Python v2 drops suport for Python 3.6, following the Python 3.6 End-Of-Life (EOL) reached on December 23, 2021.

Initial Steps

Before you start, we suggest making a copy of your current working project or create a new branch with git.

  1. Upgrade Python to at least v3.7

  2. Ensure you have the latest aws-lambda-powertools

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    pip install aws-lambda-powertools -U

  3. Review the following sections to confirm whether they affect your code

Event Handler Response (headers and cookies)

The Response class of the event handler utility changed slightly:

  1. The headers parameter now expects either a value or list of values per header (type Union[str, Dict[str, List[str]]])
  2. We introduced a new cookies parameter (type List[str])
Note

Code that set headers as Dict[str, str] will still work unchanged.

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@app.get("/todos")
def get_todos():
    # Before
    return Response(
        # ...
        headers={"Content-Type": "text/plain"}
    )

    # After
    return Response(
        # ...
        headers={"Content-Type": ["text/plain"]},
        cookies=[Cookie(name="session_id", value="12345", secure=True, http_only=True)],
    )

Legacy SQS Batch Processor

The deprecated PartialSQSProcessor and sqs_batch_processor were removed. You can migrate to the native batch processing capability by:

  1. If you use sqs_batch_decorator you can now use batch_processor decorator
  2. If you use PartialSQSProcessor you can now use BatchProcessor
  3. Enable the functionality on SQS
  4. Change your Lambda Handler to return the new response format
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from aws_lambda_powertools.utilities.batch import sqs_batch_processor

def record_handler(record):
    return do_something_with(record["body"])

@sqs_batch_processor(record_handler=record_handler)
def lambda_handler(event, context):
    return {"statusCode": 200}

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import json

from aws_lambda_powertools.utilities.batch import BatchProcessor, EventType, batch_processor

processor = BatchProcessor(event_type=EventType.SQS)


def record_handler(record):
    return do_something_with(record["body"])

@batch_processor(record_handler=record_handler, processor=processor)
def lambda_handler(event, context):
    return processor.response()

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from aws_lambda_powertools.utilities.batch import PartialSQSProcessor
from botocore.config import Config

config = Config(region_name="us-east-1")

def record_handler(record):
    return_value = do_something_with(record["body"])
    return return_value


def lambda_handler(event, context):
    records = event["Records"]

    processor = PartialSQSProcessor(config=config)

    with processor(records, record_handler):
        result = processor.process()

    return result

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from aws_lambda_powertools.utilities.batch import BatchProcessor, EventType, batch_processor


def record_handler(record):
    return_value = do_something_with(record["body"])
    return return_value

def lambda_handler(event, context):
    records = event["Records"]

    processor = BatchProcessor(event_type=EventType.SQS)

    with processor(records, record_handler):
        result = processor.process()

    return processor.response()
Last update: 2022-09-02